let ifDone:boolean=false;
let count:number=10;
let name:string="yongqi";
let list:number[]=[1,2,3];
enum Direction{
    NORTH,
    SOUTH,
    EAST,
    WEST
}
let dir:Direction=Direction.NORTH;  // 枚举类型
let notSure:any=666;  // 任意类型
notSure="w1212";
let value:unknown;
let tupleType:[string,boolean];  //  元组
tupleType=['semlingker',true];
function warnUser():void {}
let u:undefined;
let n:null;
